<template>
    <div>
      <router-link tag="div" to="/" class="header-abs"
      v-show="showAbs"
         >
          <div class="iconfont header-black">&#xe61d;</div>
      </router-link>


      <div class="header-fixed" 
      v-show="!showAbs"
     :style = "opacityStyle"
      >
        <router-link  to="/">
         <div class="iconfont header-fixed-back">&#xe61d;</div>
     </router-link>
          景点详情
      </div>
    </div>
</template>
<script>
    export default {
      name: 'DetailHeader',
      data () {
        return {
            showAbs: true,
            opacityStyle: {
                opacity: 0
            }
        }
      },
      methods: {
         handleScroll () {
            const top =  document.documentElement.scrollTop
       if(top > 80) {
             let opacity = top / 160
             opacity = opacity > 1 ? 1 : opacity
             this.opacityStyle = { opacity }
        this.showAbs = false
       } else {
        this.showAbs = true
       }

         }
      },
      activated () {
        window.addEventListener('scroll', this.handleScroll)
      },
      deactivated () {
        window.removeEventListener('scroll', this.handleScroll)
      }
    }
</script>
<style scoped>
    .header-black {
        color: #fff;
        font-size: .8rem;
     }


    .header-fixed-back {
       position: fixed;
        top: 0;
        left: 0;
        right: 0;
        width: .64rem;
        text-align: center;
        font-size: .4rem;
        color: #fff;
    }



    .header-abs {
        position: absolute;
        left: .2rem;
        top: .2rem;
        width: .8rem;
        height: .8rem;
        border-radius: .4rem;
        text-align: center;
        line-height: .8rem;
        background: rgba(0,0,0,.8);
    }

    .header-fixed {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        height: .86rem;
        overflow: hidden;
        line-height: .86rem;
        text-align: center;
        color: #fff;
        background: #00bcd4;
        font-size: .32rem;
    }

 



</style>